1. Field of the Invention
The present invention relates to an image pickup apparatus including a display unit, such as a digital camera. More specifically, the present invention relates to the display of setting items on the display unit during photographing.
2. Description of the Related Art
Photographing under various conditions has been performed using digital cameras or film cameras, such as photographing with natural light in daytime, photographing with flash light in which a flash of light is emitted to illuminate an object in the dark, and daylight synchronization in which photographing with both natural light and flash light is performed.
Besides normal photographing with appropriate exposure (hereinafter referred to as “correct exposure”) under the above-described conditions, for example, a photographer may expose an object for a time shorter than the correct exposure time, i.e., underexposure, in order to achieve high-quality photographic effects. Inversely, a photographer may expose an object for a time longer than the correct exposure time, i.e., overexposure. In view of such various photographic situations, image pickup apparatuses and external flash devices capable of performing exposure control according to photographers' intentions have been proposed and are now widely used.
Japanese Patent Laid-Open No. 2003-043559 discloses an image pickup apparatus including an operation member capable of appropriately setting an amount of correction for a fixed amount of light emission or calculated light-control value of an external flash device (hereinafter referred to as light-control correction value). According to a technique employed in the image pickup apparatus, even if the external flash device does not have a function of setting the fixed amount of light emission, the fixed amount of light emission can be appropriately set by operating the image pickup apparatus.
It is assumed that an external flash device is connected to a camera to set a light-control correction value of the external flash device using the camera. If the external flash device has been powered on, the camera is operated to display, on a display unit of the camera, a menu for setting the light-control correction value of the external flash device to change a set value.
FIG. 8 shows an example of a display screen of a display unit disposed on a rear surface of a camera for displaying a window for setting a light-control correction value of an external flash device. A specific button of the camera is operated to display a list of icons indicating frequently used functions on the display unit disposed on the rear surface of the camera where an image of an object is displayed. Examples of the frequently used functions include a white balance setting, a photometric setting, and a light-control correction setting. In FIG. 8, the icons are vertically arranged side-by-side along the left edge of the screen of the display unit. The icon corresponding to the light-control correction setting is placed in the fourth row from the top. When an indicator moving over the icons is moved and the icon corresponding to the light-control correction setting is selected, specific setting values are displayed on a lower portion of the screen of the display unit so that a user can select a desired value.
Some cameras are capable of switching the operating state of an external flash device attached to the cameras between a power-on state and a power-off state to determine whether to emit light from the external flash device during photographing.
Similarly to FIG. 8, FIG. 9A shows a screen of a display unit for allowing a user to set, using a camera, a light-control correction value of an external flash device attached to the camera after the user powers on the external flash device. If the external flash device is powered off in this state, the setting of the light-control correction value using the camera is disabled.
Japanese Patent Laid-Open No. 2001-054006 discloses a technique in which, as shown in FIG. 9B, the display of an icon corresponding to a function that is not available for selection is changed from highlighted to grayed out to change the state of the icon to a non-active state so that a user can easily recognize an item that is not available for selection. In accordance with the change of the display, the indicator located on the icon indicating the light-control correction setting in the manner shown in FIG. 9A is moved to the below icon indicating another function (in this example, the photometric setting) in the manner shown in FIG. 9B.
In the technique disclosed in Japanese Patent Laid-Open No. 2001-054006, even if the external flash device is powered on again to perform flash light photographing, the indicator is still located on the icon indicating the photometric setting, which is displayed below the icon indicating the light-control correction setting. That is, in order to set a light-control correction value, it is necessary to power on the external flash device and to move the indicator located on the icon indicating the photometric setting to the icon indicating the light-control correction setting.
Accordingly, due to the bothersome procedure of selecting a menu for setting a light-control correction value, it is difficult to smoothly perform photographing under varying photographic conditions using the determination of whether to emit light from an external flash device and using light-control correction during flash light photographing.
Further, regardless of whether an external flash device is used, if an indicator is moved from a selected setting item due to a change of the photographic conditions, a time-consuming operation of moving the indicator to the selected setting item again is required.